1. Field of the Invention
The present invention relates to an optical element position adjusting mechanism and an optical element position adjusting method, an exposure apparatus using the same, and a device manufacturing method.
2. Description of the Related Art
In an exposure apparatus, a superposition of patterns may necessitate a mechanism for adjusting the position of an optical element with high accuracy. As a mechanism for adjusting the position of an optical element, measurements by a sensor and a feedback control using these measurement results have been conventionally employed in order to achieve highly accurate positioning and at the same time to achieve high position stability. Japanese Patent Laid-Open No. 2008-242448 discloses an exposure apparatus having a mechanism which employs in combination a feedback control using a sensor and an actuator, and a flexure guide. In this case, an improvement is made such that the mechanism becomes less prone to drive in a direction other than the driving direction with the aid of the flexure guide, whereby more highly accurate positioning can be achieved.
However, the technique disclosed in Japanese Patent Laid-Open No. 2008-242448 requires a permanent inclusion of a sensor, and thus, the degree of freedom in disposing a sensor may be undesirably limited depending on the wiring of the sensor. Likewise, an electrical system for performing feedback control may also be required, whereby the overall apparatus to which an optical element position adjusting mechanism is mounted, and the overall size of the exposure apparatus may thereby become enlarged. Furthermore, maintenance may become difficult due to wiring.